department. the watertown police department is also involved. >> here is what we know about dzhokhar tsarnaev the suspect still at large. he is 19 years old, the brother of suspect number one. he is from russia, chechnya. he has been in the u.s. for about 10 years. this photo was taken born a robbery at a 7-eleven in cambridge last night. >> many residents in the area witness the car chase and the explosion with the suspects. here's one resident described in what he saw and what he heard. >> the shootout with police in the up with the death of older brother and a lot of residents heard this trace and heard the explosion and the gunfire when this went down. >> i thought i heard firecrackers. i heard gunshots and then i saw the explosion. i actually saw a black suv go down the street. it looked like it had hit a police car and they were just shooting at a. i must occur about 60 gunshots. >> what was the explosion like? >> it shook my house. >> supporters are urging residents and watertown, new town, waltham, bill mott, a cambridge and boston austin bryson neighborhood of boston to stay indoors.